The present invention relates to the use of mixtures of micronized organic UV filters for preventing tanning and for lightening human skin and hair and to their use in cosmetic and pharmaceutical formulations.
It is known that certain organic UV filters, for example sparingly soluble benzotriazole or triazine compounds, have excellent UV filter properties if they are in micronized form.
Particularly in Asiatic countries, there is great interest in light protection filters or mixtures of light protection filters which preserve the colour of the skin following solar irradiation and, moreover, are able to impart a lighter appearance to the skin.
The object of the present invention is therefore to find micronized organic UV filters which prevent tanning of the skin and at the same time are able to lighten the skin.
Surprisingly, we have now found that micronized organic UV filters or mixtures of at least two micronized UV filters can achieve this object.
The present invention therefore provides for the use of mixtures of micronized organic UV filters for preventing tanning and for lightening of human skin.
Suitable UV filters which can be used according to the invention are organic, sometimes sparingly soluble, compounds, for example triazine derivatives, in particular hydroxyphenyltriazine compounds or benzotriazole derivatives, amides containing a vinyl group, cinnamic acid derivatives, sulfonated benzimidazoles, Fischer base derivatives, diphenylmalonitriles, oxalylamides, camphor derivatives, diphenylacrylates, paraaminobenzoic acid (PABA) and derivatives thereof, salicylates, benzophenones and also other classes of substance known as UV filters.
Preferred triazine derivatives which can be used according to the invention correspond to the formula 
in which
R1, R2 and R3, independently of one another, are hydrogen; OH; C1-C18alkoxy; xe2x80x94NH2; xe2x80x94NHxe2x80x94R4; xe2x80x94N(R4)2; xe2x80x94OR4,
R4 is C1-C5alkyl; phenyl, phenoxy, anilino or pyrrolo which are unsubstituted or substituted by one, two or three OH groups, carboxyl, xe2x80x94COxe2x80x94NH2, C1-C5alkyl or C1-C5alkoxy; a methylidenecamphor group; a group of the formula xe2x80x94(CHxe2x95x90CH)mC(xe2x95x90O)xe2x80x94OR4; a group of the formula 
xe2x80x83or the corresponding alkali metal, ammonium, mono-, di- or tri-C1-C4alkylammonium, mono-, di- or tri-C2-C4alkanolammonium salts, or C1-C3alkyl esters thereof; or a radical of the formula (1a) 
R5 is hydrogen; unsubstituted C1-C5alkyl or C1-C5alkyl substituted by one or more OH groups; C1-C5alkoxy; amino; mono- or di-C1-C5alkylamino; M; a radical of the formula 
Rxe2x80x2, Rxe2x80x2 and Rxe2x80x2xe2x80x3, independently of one another, are unsubstituted C1-C14alkyl or C1-C14alkyl substituted by one or more OH groups;
R6 is hydrogen; M; C1-C5alkyl; or a radical of the formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94T1;
M is a metal cation;
T1 is hydrogen; or C1-C8alkyl;
m is 0 or 1
m2 is 1 to 4; and
m3 is 2to 14.
Further preferred triazine derivatives which can be used according to the invention correspond to the formula 
in which
R7 and R8, independently of one another, are C1-C18alkyl; C2-C18alkenyl; a radical of the formula xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; or
R7 and R8 are a radical of the formula (2a) 
R9 is the direct bond; a straight-chain or branched C1-C4alkylene radical or a radical of the formula xe2x80x94Cm1H2m1xe2x80x94Oxe2x80x94;
R10, R11, and R12, independently of one another, are C1-C18alkyl; C1-C18alkoxy or a radical of the formula 
R13 is C1-C5alkyl;
m1 is 1 to 4;
p1 is 0 to 5;
A1 is a radical of the formula 
xe2x80x83or of the formula 
R14 is hydrogen; C1-C10alkyl, xe2x80x94(CH2CHR16xe2x80x94O)n1xe2x80x94R15; or a radical of the formula xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R15 is hydrogen; M; C1-C5alkyl; or a radical of the formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94(CH2)m3xe2x80x94T1;
R16 is hydrogen; or methyl;
T1 is hydrogen; or C1-C8alkyl;
Q1 is C1-C18alkyl;
M is a metal cation;
m2 and m3, independently of one another, are 1 to 4; and
n1 is 1 to 16.
Very particularly preferred triazine derivatives of the formula (2) correspond to the formulae 
in which
R17 and R18, independently of one another, are C3-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1-C10alkyl or a radical of the formula 
R20 is hydrogen; M; C1-C5alkyl; xe2x80x94NHxe2x80x94C1-C5alkyl; preferably xe2x80x94NH-tert-alkyl; or a radical of the formula xe2x80x94(CH2)mxe2x80x94Oxe2x80x94T2;
T1 and T2, independently of one another, are hydrogen; or C1-C5alkyl; and
m is 1 to 4.
Of very particular interest are compounds of the formula (2a) and (2b) in which
R17 and R18, independently of one another, are C1-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1-C10alkyl;
and compounds of the formula (2c) and (2d) in which
R17 and R18, independently of one another, are C1-C18alkyl or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; and
T1 is hydrogen; or C1-C5alkyl.
Of the utmost interest are triazine compounds of the formula (2a)-(2d) in which R17 and R18 have the same meanings.
Further interesting triazine compounds which can be used according to the invention correspond to the formula 
in which
R21 is C1-C30alkyl; C2-C30alkenyl; unsubstituted C5-C12cycloalkyl or C5-C12cycloalkyl mono- or polysubstituted by C1-C5alkyl; C1-C5alkoxy-C1-C12alkyl; amino-C1-C12alkyl; C1-C5monoalkylamino-C1-C12alkyl; C1-C5dialkylamino-C1-C12alkyl; a radical of the formula (3a) 
xe2x80x83or (3b) 
xe2x80x83in which
R22, R23 and R24, independently of one another, are hydrogen, xe2x80x94OH; C1-C30alkyl, C2-C30alkenyl,
R25 is hydrogen; or C1-C5alkyl;
m1 is 0 or 1; and
n1 is 1 to 5.
Preferred compounds correspond to the formula 
r and s, independently of one another, are 0 to 20.
Examples of triazine derivatives which can be used according to the invention correspond to the formulae 
and also 2,4,6-tris(diisobutyl-4xe2x80x2-aminobenzalmalonate)-s-triazine and 2,4-bis(diisobutyl-4-aminobenzalmalonate)-6-(4xe2x80x2-aminobenzylidenecamphor)-s-triazine.
Likewise preferred triazine compounds which can be used according to the invention are described in EP-A-654469, for example the compound of the formula 
According to the invention, particularly suitable triazine compounds are those described, for example, in EP-A-0,818450, for example the compound of the formula 
Very particularly preferred triazine derivatives which can be used according to the invention correspond to the formula 
R27, R28 and R29, independently of one another, are a radical of the formula 
R30 is hydrogen; alkali metal; an ammonium group xe2x80x94N(R33)4,
R33 is hydrogen; C1-C5alkyl; or a polyoxyethylene radical which has 1 to 10 ethylene oxide units and the terminal OH group can be etherified with a C1-C5alcohol;
R31 is hydrogen; xe2x80x94OH; or C1-C6alkoxy;
R32 is hydrogen or xe2x80x94COOR30; and
n is 0 or 1.
If R30 is alkali metal, this is in particular potassium or very particularly sodium. (R33)4 is in particular a mono-, di- or tri-C1-C4alkylammonium salt, a mono-, di- or tri-C2-C4alkanol-ammonium salt or a C1-C3alkyl ester thereof.
If R33 is a C1-C3alkyl group, this is in particular a C1-C2alkyl group, in particular a methyl group, and if R33 is a polyoxyethylene radical, then the latter contains in particular 2 to 6 ethylene oxide units.
Preferred benzotriazole compounds which can be used according to the invention correspond to the formula 
T1 is C1-C5alkyl or, preferably, hydrogen; and
T2 is C1-C5alkyl, preferably t-butyl, or phenyl-substituted C1-C4alkyl, in particular xcex1,xcex1-dimethylbenzyl.
A further preferred class of benzotriazole compounds which can be used according to the invention corresponds to the formula 
T2 is as defined in formula (26).
Other very particularly preferred benzotriazole compounds which can be used according to the invention correspond to the formula 
T2 is as defined in formula (26) and is preferably methyl, t-butyl or isooctyl.
Preferred vinyl-containing amides which can be used according to the invention correspond to the formula
R33xe2x80x94(Y)mxe2x80x94COxe2x80x94C(R34)xe2x95x90C(R35)xe2x80x94N(R36)(R37),xe2x80x83xe2x80x83(29)
in which
R33 is C1-C5alkyl, preferably methyl or ethyl, or unsubstituted phenyl or phenyl substituted by one, two or three of the radicals OH, C1-C5alkyl, C1-C5alkoxy or COxe2x80x94OR33;
R34, R35, R36 and R37, independently of one another, are C1-C5alkyl, preferably methyl or ethyl; or hydrogen;
Y is xe2x80x94NH or xe2x80x94Oxe2x80x94; and
m is as defined above.
Preferred compounds of the formula (29) are 4-methyl-3-penten-2-one, ethyl 3-methyl-amino-2-butenoate, 3-methylamino-1-phenyl-2-buten-1-one and 3-methylamino-1-phenyl-2-buten-1-one.
Preferred cinnamides which can be used according to the invention correspond to the formula 
R38 is hydrogen or C1-C5alkoxy, preferably methoxy or ethoxy;
R39 is hydrogen or C1-C5alkyl, preferably methyl or ethyl; and
R40 is xe2x80x94(CONH)m-phenyl, in which m is as defined above, and the phenyl group is unsubstituted or substituted by one, two or three of the radicals OH, C1-C3alkyl, C1-C3alkoxy or COxe2x80x94OR30.
R40 is preferably phenyl, 4-methoxyphenyl or the phenylaminocarbonyl group.
Further preferred cinnamic acid derivatives are 2-ethylhexyl 4-methoxycinnamate or isoamylate or inter alia the cinnamic acid derivatives disclosed in U.S. Pat. No. 5,601,811 and WO 97/00851.
Preferred sulfonated benzimidazoles which can be used according to the invention correspond to the formula 
M is hydrogen or an: alkali metal, preferably sodium, an alkaline earth metal, for example magnesium or calcium, or zinc.
Preferred Fischer base aldehydes which can be used according to the invention correspond to the formula 
R41 is hydrogen; C1-C5alkyl; C1-C18alkoxy; or halogen;
R42 is C1-C8alkyl; C5-C7cycloalkyl; or C6-C10aryl;
R43 is C1-C18alkyl or a radical of the formula (32a) 
R44 is hydrogen; or a radical of the formula 
R45 is 
xe2x80x83C1-C18alkoxy; or a radical of the formula 
R46 and R47, independently of one another, are hydrogen; or C1-C5alkyl;
R48 is hydrogen; C1-C5alkyl; C5-C7cycloalkyl; phenyl; phenyl-C1-C3alkyl;
R49 is C1-C18alkyl;
X is Hal; a radical of the formula (32c) 
n is 0 or 1.
Further compounds which can be used with preference correspond to the formula 
R50, R51, R52, R53, R54, independently of one another, are hydrogen, C1-C8alkyl or C5-C10cycloalkyl;
R55 is hydrogen; C1-C8alkyl; C5-C10cycloalkyl; hydroxyl; C1-C8alkoxy; COOR56; or
R56, R57 and R58, independently of one another, are hydrogen or C1-C6alkyl;
X and Y, independently of one another, are hydrogen, xe2x80x94CN; CO2R59; CONR59R60; or COR59; where the radicals X and Y may additionally be a C1-C8alkyl radical, a C5-C10alkyl radical, in particular phenyl, or a heteroaryl radical having 5 to 6 ring atoms, where, in addition, X and Y or
R50 together with one of the radicals X and Y can represent the radical to complete a 5- to 7-membered ring which may contain up to 3 heteroatoms, in particular oxygen and/or nitrogen, where the ring atoms may be substituted, in particular by exocyclically double-bonded oxygen (keto oxygen) and/or C1-C8alkyl and/or C5-C10cycloalkyl radicals, and/or may contain Cxe2x95x90C double bonds;
Z is hydrogen; ammonium; alkali metal ion; in particular lithium, sodium, potassium, 1/2 equivalents of alkaline earth metal ion, preferably calcium, magnesium or the cation of an organic nitrogen base used to neutralize the free acid group,
R59 and R60, independently of one another, are hydrogen, C1-C8alkyl or C5-C10cycloalkyl; and
n and m, independently of one another, are 0 or 1.
Preferred diphenylmalonitriles which can be used according to the invention correspond to the formula 
R61 and R62, independently of one another, are C1-C12alkyl; or C1-C12alkoxy; and
n is 0-3.
Other organic UV filters which can be used according to the invention correspond to the formula 
R63 and R64, independently of one another, are C1-C5alkyl, in particular ethyl.
Other preferred chemical compound classes of UV filters which can be used according to the invention are:
p-aminobenzoic acid derivatives (PABA), in particular 2-ethylhexyl 4-dimethylamino-benzoate;
salicylic acid derivatives, in particular 2-ethylhexyl salicylates; homosalates; and isopropyl salicylates;
benzophenone derivatives, in particular benzophenone-2, -3, and -4;
dibenzoylmethane derivatives, in particular 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-propane-1,3-dione or butylmethoxydibenzoylmethane;
diphenylacrylates, in particular 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, ethyl 2-cyano-3,3xe2x80x2-diphenylacrylate and 3-(benzofuranyl) 2-cyanoacrylate;
3-imidazol-4-ylacrylic acid and 3-imidazol-4-yl acrylate;
benzofuran derivatives, in particular the p-aminophenylbenzofuran derivatives published in EP-A-582,189, U.S. Pat. Nos. 5,338,539 and 5,518,713;
camphor derivatives, in particular 3-(4xe2x80x2-methyl)benzylidenebornan-2-one, 3-benzyidenebornan-2-one, N-[2(and 4)-2-oxyborn-3-ylidenemethyl)benzyl]acrylamide polymer, 3-(4xe2x80x2-trimethylammonium)benzylidenebornan-2-one methylsulfate, 3,3xe2x80x2-(1,4-phenylenedimethine)-bis(7,7-dimethyl-2-oxobicyclo[2.2.1]heptane-1-methanesulfonic acid) and salts thereof, 3-(4xe2x80x2-sulfo)benzylidenebornan-2-one and salts thereof; and
menthyl o-aminobenzoate.
The UV filters listed above can be used according to the invention as individual compounds or also, preferably, as mixtures.
Preference is given to using the following mixtures of organic UV filters:
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol and octyltriazone;
mixtures of octyltriazone and methylenebisbenzotriazolyltetramethylbutylphenol;
mixtures of 2-[(2,4-methoxy)phenyl]-4,6-bis[(2-hydroxy-4-methoxy)phenyl]-(1,3,5)triazine and methylenebisbenzotriazolyltetramethylbutylphenol;
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol and dioctylbutamidotriazone;
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol and octyl-2,2xe2x80x2-methylenebis[6-(2H-benzotriazol-2-yl)-4-methylphenol,
mixtures of octyltriazone and trisresorcinyltriazine;
mixtures of 2,2xe2x80x2-methylenebis[6-(2H-benzotriazol-2-yl)-4-methylphenol, octyltriazone and the compound of the formula (36) 
mixtures of 2,2xe2x80x2-methylenebis[6-(2H-benzotriazol-2-yl)-4-methylphenol, octyltriazone and the compound of the formula (37) 
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol, octyltriazone and the compound of the formula (38) 
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol and the compound of the formula (39) 
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol, dioctylbutamidotriazone and the compound of the formula (37).
In the radicals defined above, C1-C18alkyl are straight-chain or branched alkyl radicals, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, amyl, isoamyl or tert-amyl, heptyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl.
C1-C18Alkoxy radicals are straight-chain or branched alkyl radicals, for example methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, amyloxy, isoamyloxy or tert-amyloxy, heptyloxy, octyloxy, isooctyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy, heptadecyloxy or octadecyloxy.
C2-C18Alkenyl is, for example, allyl, methallyl, isopropenyl, 2-butenyl, 3-butenyl, isobutenyl, n-penta-2,4-dienyl, 3-methylbut-2-enyl, n-oct-2-enyl, n-dodec-2-enyl, isododecenyl, n-dodec-2-enyl or n-octadec-4-enyl.
The mixtures of micronized organic UV filters which can be used according to the invention can be prepared in different ways.
Firstly, at least two of the abovementioned organic UV filters can be mixed as individual substances in the preparation process of the microparticles (micronization).
Another preparation option involves thoroughly mixing the already micronized individual substances of the UV filters together.
A third preparation option involves melting together at least two of the abovementioned UV filters. Cooling the melt produces a homogeneous composite, which is micronized in the usual manner.
The homogeneous composites of at least two organic UV filters are also provided by the invention.
The invention further provides composites obtainable by fusing one or more inorganic micropigments into one or more organic UV filters.
Examples of micropigments are, for example, TiO2, ZnO, iron oxides or other inorganic oxides, mica or other suitable inorganic minerals, and also Ti, alkaline earth metal or zinc salts of organic acids.
In so doing, the undesired photocatalytic properties of some of these inorganic micropigments (TiO2, ZnO) can be simultaneously suppressed, and their positive properties can also be fully utilized.
The abovementioned inorganic UV filters are advantageously fused into methylenebisbenzotriazolyltetramethylbutylphenol. The resulting composite is then micronized in the usual manner.
The invention further provides composites obtainable by melting at least two electrically neutral organic UV filters with cationically or anionically charged compounds.
For this, cationically or anionically charged compounds are melted with the corresponding organic, electrically neutral UV filters and then cooled. This process permits, in the subsequent micronization step, the preparation of organic UV filter pigments having a permanent finishing of a positive or negative charge. Such a finishing effectively prevents aggregation of the micronized particles in the sunscreen preparations which can occur in cases where the particle diameter is  less than 1 xcexcm. An otherwise customary xe2x80x9ccoatingxe2x80x9d of these particles having a repelling effect then sometimes becomes superfluous.
Cationically or anionically charged compounds which can be used are UV filters and also other compounds which have one or more cationic or anionic groups, for example
N,N,N-trimethyl-4-(2-oxoborn-3-ylidenemethyl)aniline methylsulfate;
camphorbenzalkonium methosulfate;
fatty amines;
betaines, for example cocamidopropylbetaine;
quats, for example ricinoleamidopropyltrimonium methosulfate, Quarternium 18, or cetyltrimethylammonium bromide;
behenic acid and other organic acids, for example isostearic acid, citricmonoglyceride or sodium methyl cocoyl taurate;
phospholipids, for example phosphatidylcholine, phosphatidylserine or alkylamine oxide;
ceramides and pseudoceramides and phytosterols.
The last-named compounds impart an oleophobic finishing to the micronized UV filters.
The proportion of cationic or anionic compounds in the composite is between 0.001 and 5% by weight, preferably 0.01 to 3% by weight, based on the weight of the UV filter(s).
The invention further provides composites obtainable by melting at least one sparingly soluble or insoluble organic UV filter with antoxidants.
For this, the sparingly soluble or insoluble organic UV filter(s) is/are melted together with antioxidants, cooled and then micronized in the usual manner.
Suitable antioxidants which can be used according to the invention are all organic substances having scavenger properties which can be melted together with organic UV filters. This gives novel types of micropigments which simultaneously prevent tanning of the skin and offer antioxidative action on its surface. This property is desired for cosmetic sun protection since, under the influence of UV and light, harmful free radicals can be formed both in formulations and on the skin. These can, for example, lead to so-called Mallorca acne or to premature skin ageing. By finishing the micronized UV filters with antioxidants, not only is protection against UV damage and prevention of tanning achieved, but also protection against photochemical degradation of constituents in the sunscreen formulation.
The proportion of antioxidants in the composite is generally between 0.001 and 30% by weight, preferably 0.01 to 3% by weight, based on the weight of the UV filter(s).
A content of antioxidants is particularly advantageous in micropigments which, in addition to organic UV filters, comprise the abovementioned photocatalytically active inorganic micropigments, for example titanium dioxide, zinc oxide (including coated) or other suitable inorganic oxides, for example iron oxide.
Examples of antioxidants which may be listed are the following compounds:
tocopherols, for example xcex1-tocopherol (CAS 59-02-9), tocopheryl acetate, vitamin E succinate,
ellagic acid 
propyl gallate (CAS 121-79-9) 
N-butylated hydroxytoluene (BHT; CAS 128-37-0);
butylated hydroxyanisole (BHA);
2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)mesitylene (CAS 1709-70-2) 
tetrakis[methylene-3(3xe2x80x2,5xe2x80x2-di-t-butyl-4xe2x80x2-hydroxyphenyl)propionate]methane (CAS 6683-19-8);
compound of the formula 
compound of the formula 
compound of the formula
vanillin;
ubiquinone;
ferulic acid and derivatives;
rutic acid and derivatives;
urocanic acid and derivatives; and
propolis.
Preference is given to using the following mixtures of antioxidants and organic UV filters:
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol, octyltriazone, titanium dioxide and tocopherol,
mixtures of 2,2xe2x80x2-methylenebis[6-(2H-benzotriazol-2-yl)4-methylphenol, octyltriazone, trisresorcinyltriazine and vitamin E
mixtures of methylenebisbenzotriazolyltetramethylbutylphenol, octyltriazone, compound of the formula (103) 
(xe2x80x9cFischer aldehydexe2x80x9d) and compound of the formula 
The invention further provides composites obtainable by fusing meltable cosmetic, vegetable and pharmaceutical active ingredients into organic UV filters.
In general, micronized UV filters can be used as carriers of highly active substances, in particular cosmetic and/or pharmaceutical active substances. The advantage of such composites lies in the fact that it is possible for them to release the active substance(s) from the solid (slow release). A slow release also guarantees the uniform effectiveness of highly active active ingredients, for example antiinflammatories, care active ingredients or trace elements, for example Zn2+ or Mg2+, over the entire useful life of the UV pigments.
Examples of active ingredients which can be used and which may be mentioned are:
active ingredients for antimicrobial finishing and simultaneous antiinflammatory action, for example triclosan or diclosan;
antiinflammatory active ingredients, for example farnesol, panthenol or avocado oil;
active ingredients having a deodorant or antiperspirant action, for example Zn ricinoleates and alkyl citrates,
undecylenic acid and derivatives thereof (e.g. diethanolamides)
zinc undecylate;
pyrithiones, for example sodium pyrithione;
fused-in fragrances or fragrance mixtures, for example menthol, geraniol etc., which impart a permanent odour which is uniform in intensity to these micropigments and the formulations which comprise them.
To prepare the micronized organic UV filters or the micropigment mixtures, it is possible to use all known processes which are suitable for the preparation of microparticles, for example:
wet grinding with a hard grinding medium, for example zirconium silicate and a protective surfactant or a protective polymer in water or a suitable organic solvent;
spray drying from a suitable solvent, for example aqueous or organic suspensions containing solvent, or true solutions in water, ethanol, dichloroethane, toluene, N-methylpyrrolidone etc.;
by expansion of supercritical liquids (e.g. CO2) in accordance with the RESS process (Rapid Expansion of Supercritical Solutions) in which the UV filter(s) is/are dissolved or expansion of liquid carbon dioxide together with a solution of one or more UV filters in a suitable organic solvent;
by reprecipitation from suitable solvents, including supercritical liquids (GASR process=Gas Anti-Solvent Recrystallizabon/PCA process=Precipitation with Compressed Antisolvents).
Grinding apparatuses which can be used for the preparation of the micronized organic UV absorbers according to the invention are, for example, a jet, ball, vibratory or hammer mill, preferably a high-speed stirred mill. Grinding preferably takes place using a grinding auxiliary, for example an alkylated vinylpyrrolidone polymer, a vinylpyrrolidone/vinyl acetate copolymer, an acyl glutamate, an alkyl polyglucoside, ceteareth-25 or, in particular, a phospholipid.
The resulting micropigments or mixtures of micropigments usually have an average particle size of from 0.02 to 2 nm, preferably 0.05 to 1.5 nm, and very particularly from 0.1 to 1.0 nm.
Because of their lipophilicity, they can, alone or together with other soluble organic UV absorbers, be readily incorporated into oil- and fat-containing cosmetic formulations, for example oils, O/W or W/O emulsions, wax pencils or gels, by known methods.
Surprisingly, formulations are obtained which have equal or improved protective action using less or even no soluble UV absorbers.
The invention further provides a cosmetic formulation comprising a mixture of micropigments, if desired one or more antioxidants and/or inorganic pigments and/or a cationic or anionic compound, and cosmetically compatible carriers or auxiliaries.
Cosmetic formulations according to the invention include various cosmetic compositions. In particular, the following compositions are, for example, suitable:
skincare compositions, for example skin washes and cleansers in the form of bar or liquid soaps, syndets or washing pastes,
bath preparations, for example liquid (foam baths, milks, shower preparations) or solid bath preparations, for example bath tablets or bath salts;
skincare compositions, for example skin emulsions, multiple emulsions or skin oils;
decorative bodycare compositions, for example face make-up in the form of day creams or powder creams, face powder (loose or pressed), blusher or cream make-up, eyecare compositions, for example eyeshadow preparations, mascara, eyeliner, eye creams or eye-fix creams; lipcare compositions, for example lipstick, lip gloss, lip liner pencil, nailcare compositions, such as nail varnish, nail varnish remover, nail hardeners or cuticle removers;
personal hygiene care compositions, for example personal hygiene washing lotions or personal hygiene sprays;
footcare compositions, for example foot baths, foot powders, foot creams or foot balsams, special deodorants and antiperspirants or products for removing calluses;
light protection compositions, such as sun milks, lotions, creams and oils, sun blocks or tropicals, pretanning preparations or aftersun preparations;
skin tanning compositions, for example self-tanning creams;
depigmentation products, for example preparations for skin bleaching or compositions for skin lightening;
insect-repelling compositions (xe2x80x9crepellentsxe2x80x9d), for example insect oils, lotions, sprays or sticks;
deodorants, such as deodorant sprays, pump sprays and deodorant gels, sticks or roller balls;
antiperspirants, for example antiperspirant sticks, creams or roller balls;
compositions for cleansing and caring for blemished skin, for example syndets (solid or liquid), peeling or exfoliation preparations or peeling masks;
depilatories in chemical form, for example depilatory powders, liquid depilatores, cream or paste depilatories, depilatories in gel form or aerosol foams;
shaving compositions, for example shaving soap, foaming shaving creams, nonfoaming shaving creams, foams, gels, preshave preparations for dry shaving, aftershaves or aftershave lotions;
fragrances, for example fragrance water (eau de Cologne, eau de toilette, eau de parfum, parfum de toilette, parfum), perfume oils or perfume creams;
compositions for dental, denture and mouth care, for example toothpastes, gel toothpastes, tooth powders, mouthwash concentrates, antiplaque mouthrinses, denture cleaners or denture adhesives;
cosmetic compositions for treating hair, for example hair cleansers in the form of shampoos, hair conditioners, haircare compositions, for example pretreatment compositions, hair tonic, styling creams, styling gels, pomades, hair rinses, treatment packs, intensive hair treatments, compositions for shaping hair, for example waving agents for the preparation of permanent waves (hotwave, mildwave, coldwave), hair-smoothing preparations, liquid hair-setting compositions, hair mousses, hair sprays, bleaching agents, for example hydrogen peroxide solutions, lightening shampoos, bleaching creams, bleaching powders, bleaching pastes or oils, temporary, semipermanent or permanent hair colorants, preparations containing self-oxidizing dyes, or natural hair colorants, such as henna or camomile.
These listed end formulations can be in the form of various application forms, for example
in the form of liquid preparations as a W/O, O/W, O/W/O, W/O/W, PIT and all other types of microemulsions,
in the form of a gel,
in the form of an oil, a cream, milk or lotion,
in the form of a powder, a lacquer, a tablet or make-up,
in the form of a stick,
in the form of a spray (spray with propellant or pump spray) or an aerosol,
in the form of a foam, or
in the form of a paste.
The cosmetic formulations according to the invention can advantageously comprise further substances which absorb UV radiation in the UVB region. The total amount of filter substances here is 0.1 to 30% by weight, preferably 0.5 to 10% by weight, in particular 1 to 6% by weight, based on the total weight of the composition.
In particular, suitable additional UVB filters are oil-soluble, nonmicronized compounds, for example organic UV absorbers from the class of p-aminobenzoic acid derivatives, salicylic acid derivatives, benzophenone derivatives, dibenzoylmethane derivatives, diphenylacrylate derivatives, benzofuran derivatives, polymeric UV absorbers, comprising one or more organosilicon radicals, cinnamic acid derivatives, camphor derivatives, trianilino-s-triazine derivatives, phenylbenzimidazolesulfonic acid and salts thereof, menthyl anthranilate, benzotriazole derivatives, and/or an inorganic micropigment chosen from zinc oxide, mica or TiO2 coated with aluminium oxide or silicon dioxide.
Examples of compounds of p-aminobenzoic acid derivatives:
4-aminobenzoic acid (PABA); ethyldihydroxypropyl-PABA of the formula 
in which m,n and x have the same meaning and are each at most 25;
octyldimethyl PABA of the formula 
xe2x80x83or glycyl aminobenzoate of the formula 
Examples of compounds of salicylic acid derivatives:
homomenthyl salicylate of the formula 
xe2x80x83triethanolamine salicylate of the formula 
xe2x80x83amyl p-dimethylamino-benzoate of the formula (10) 
xe2x80x83octyl salicylate of the formula 
xe2x80x83or 4-isopropylbenzyl salicylate of the formula 
Examples of compounds of benzophenone derivatives:
benzophenone-3-(2-hydroxy4-methoxybenzophenone), benzophenone4-(2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) or benzophenone-8-(2,2xe2x80x2-dihydroxy-4-methoxybenzophenone).
Examples of compounds of dibenzoylmethane derivatives:
butylmethoxydibenzoylmethane[1-(4-tert-butyl)-3-(4-methoxyphenyl)propane-1,3-dione].
Examples of compounds of diphenylacrylate derivatives:
octocrylene 2-ethylhexyl-2-cyano-3,3xe2x80x2-diphenylacrylate or etocrylene ethyl-2-cyano-3,3xe2x80x2-diphenylacrylate.
Examples of compounds of benzofuran derivatives:
3-benzofuranyl 2-cyanoacrylate, 2-(2-benzofuranyl)-5-tert-butylbenzoxazole or 2-(p-aminophenyl)benzofuran and, in particular, the compound of the formula 
Examples of compounds of polymeric UV absorbers which comprise one or more organosilicon radicals:
benzylidenemalonate derivatives, in particular the compound of the formula 
xe2x80x83in which
R24 is hydrogen or methoxy and
r is approximately 7; the compound of the formula 
Examples of compounds of cinnamic esters:
octyl methoxycinnamate (2-ethylhexyl 4-methoxycinnamate), diethanolamine methoxycinnamate (diethanolamine salt of 4-methoxycinnamic acid), isoamyl p-methoxycinnamate (2-isoamyl 4-ethoxycinnamate), 2,5-diisopropyl methylcinnamate or a cinnamic acid amido derivative.
Examples of compounds of camphor derivatives:
4-methylbenzylidenecamphor [3-(4xe2x80x2-methyl)benzylidenebornan-2-one],
3-benzylidenecamphor (3-benzylidenebornan-2-one),
polyacrylamidomethylbenzylidenecamphor {N-[2(and 4)-2-oxyborn-3-ylidene-methyl)benzyl]acrylamide polymer}, trimoniumbenzylidenecamphor sulfate [3-(4xe2x80x2-trimethylammonium)benzylidenebornan-2-one methylsulfate], terephthalylidene-dicamphorsulfonic acid {3,3xe2x80x2-(1,4-phenylenedimethine)bis(7,7-dimethyl-2-oxobicyclo[2.2.1]heptane-1-methanesulfonic acid} or salts thereof, or benzylidene-camphorsulfonic acid [3-(4xe2x80x2-sulpho)benzylidenebornan-2-one] or salts thereof.
Examples of compounds of trianilino-s-triazine derivatives:
octyltriazine[2,4,6-trianilino(p-carbo-2xe2x80x2-ethyl-1xe2x80x2-oxy)-1,3,5-triazine, and the trianilino-s-triazine derivatives described in U.S. Pat. Nos. 5,332,568, 5,252,323, WO 93/17002 and WO 97/03642 and EP-A-0,517,104.
Examples of compounds of benzotriazoles:
2-(2-hydroxy-5-methylphenyl)benzotriazole.
The examples below serve to illustrate the invention without limiting it thereto. The cosmetic active substances are primarily given with their INCI name (INCI=International Nomenclature of Cosmetic Ingredients).